The realization of reliable battery chemistries beyond the present Li-ion systems is an important goal in the field of energy conversion and storage. The theoretical metrics of a rechargeable battery using a metallic magnesium (Mg) anode (3832 mAh/cm3 volumetric and 2205 mAh/g gravimetric capacities) have motivated significant efforts to develop electrolytes and cathode materials for secondary Mg batteries. The fundamental requirement for an electrolyte to be compatible with the electro-chemistries of both the cathode and anode is not trivially met in Mg-based systems. For instance, simple Mg electrolytes analogous to those of typical Li battery chemistries have yet to show reversible electrodeposition of Mg metal. To date, most reported Mg electrolytes have been derived from organometallic sources, predominantly Grignard reagents or analogues, often in concert with AlRxCl3−x (R=alkane or aryl group) to provide increased oxidative stability. In some recent systems, the [(μ-Cl)3Mg2(THF)6]+ dimer and/or the [MgCl(THF)5+] monomer have been implicated in producing reversible electrochemical deposition and dissolution. These various systems have shown reversible electrodeposition of dendrite-free Mg with high coulombic efficiencies and reasonable oxidative stabilities. However, halide electrolytes can be corrosive toward typical current collecting metals, limiting their commercial applicability. Many Mg electrolytes also have unattractive safety characteristics due to use of Grignards and/or tetrahydrofuran (THF) in the electrolyte. Accordingly, improved Mg battery electrolytes and electrochemical systems utilizing the same remain desirable.